EP0170828A2 - Verfahren zum Überwachen der Vorwärmzone eines Tunnelofens - Google Patents

Verfahren zum Überwachen der Vorwärmzone eines Tunnelofens Download PDF

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Publication number
EP0170828A2
EP0170828A2 EP85107266A EP85107266A EP0170828A2 EP 0170828 A2 EP0170828 A2 EP 0170828A2 EP 85107266 A EP85107266 A EP 85107266A EP 85107266 A EP85107266 A EP 85107266A EP 0170828 A2 EP0170828 A2 EP 0170828A2
Authority
EP
European Patent Office
Prior art keywords
kiln
air
preheating zone
combustion gas
ceiling
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP85107266A
Other languages
English (en)
French (fr)
Other versions
EP0170828B1 (de
EP0170828A3 (en
Inventor
Tatsuhiro Kosugi
Takeshi Ogawa
Norio Tanaka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toto Ltd
Original Assignee
Toto Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=14830447&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0170828(A2) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Toto Ltd filed Critical Toto Ltd
Publication of EP0170828A2 publication Critical patent/EP0170828A2/de
Publication of EP0170828A3 publication Critical patent/EP0170828A3/en
Application granted granted Critical
Publication of EP0170828B1 publication Critical patent/EP0170828B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/12—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity with special arrangements for preheating or cooling the charge
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories or equipment specially adapted for furnaces of these types
    • F27B9/3005—Details, accessories or equipment specially adapted for furnaces of these types arrangements for circulating gases
    • F27B9/3011—Details, accessories or equipment specially adapted for furnaces of these types arrangements for circulating gases arrangements for circulating gases transversally
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories or equipment specially adapted for furnaces of these types
    • F27B9/40—Arrangements of controlling or monitoring devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/12—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity with special arrangements for preheating or cooling the charge
    • F27B2009/122—Preheating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/20—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path
    • F27B9/26—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path on or in trucks, sleds, or containers
    • F27B9/262—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path on or in trucks, sleds, or containers on or in trucks
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D9/00—Cooling of furnaces or of charges therein
    • F27D2009/007—Cooling of charges therein
    • F27D2009/0072—Cooling of charges therein the cooling medium being a gas
    • F27D2009/0075—Cooling of charges therein the cooling medium being a gas in direct contact with the charge
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • F27D2019/0028—Regulation
    • F27D2019/0068—Regulation involving a measured inflow of a particular gas in the enclosure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • F27D2019/0028—Regulation
    • F27D2019/0078—Regulation of the speed of the gas through the charge

Definitions

  • the present invention relates to a tunnel kiln for continuously firing ceramic products, and more particularly, to a method for controlling a preheating zone of the tunnel kiln.
  • a tunnel kiln there are generally three zones, the preheating, firing and cooling zones, having a heat curve over the whole thereof so as to fire products during their passage through these zones.
  • the combustion gas may be drawn from the firing zone into the preheating zone by sucking the combustion gas, as much as possible, through suction ports in the side walls of the kiln at the lower temperature area of the preheating' zone to efficiently conduct heat exchange between the combustion gas and products.
  • a negative pressure may be created in the lower portion of the preheating zone because of the buoyancy of the combustion gas.
  • This negative pressure may increase due to the suction of the combustion gas into the flues, so that cold air violently flows through an inlet of the kiln and an underground passage into the preheating zone, resulting in an increase in the temperature difference between the hotter upper portion and the cooler lower portion of the kiln preheating zone.
  • the increased vertical temperature gradient may cause the products to be exposed at their upper portion to a higher temperature and at their lower portion to a lower temperature. For this reason, at the stage of evaporation of deposited water and water of crystallization, a difference in shrinkage of volume is produced between the interior and exterior as well as between the upper and lower portions of the products to cause internal strain in the products, so that defects such as cracks or the like may be easily generated in the products.
  • this object is accomplished by providing a method for controlling a preheating zone of a tunnel kiln, wherein air is forcedly blown downwardly from the entire ceiling portion of the kiln at the preheating zone at a flow rate dependent on the quantity of the combustion gas within the kiln preheating zone to diffuse the hot combustion gas present in the upper portion to the lower portion of the preheating zone, thereby reducing the vertical temperature gradient in the preheating zone.
  • the blowing of air is conducted by feeding air from its source provided outside the kiln into air blowing means which are arranged at appropriate intervals throughout the ceiling of the kiln at the preheating zone and extend in the direction perpendicular to the longitudinal axis of the kiln.
  • a tunnel kiln for ceramic products to which is applied a method for controlling a preheating zone according to the present invention.
  • the tunnel kiln comprises three zones: a preheating zone A, a firing zone B and cooling zone C, as shown in Fig. 1.
  • the kiln is provided with flue suction ports 8 formed in the side walls thereof, through which the combustion gas is sucked from the firing zone B into flues 6 so that it is drawn into the preheating zone A.
  • the suction of the combustion gas into the flues 6 is controlled by dampers 7 for opening and closing the suction ports 8.
  • the preheating zone is provided with a plurality of perforated hollow pipes 2 extending in the direction perpendicular to the longitudinal axis of the kiln and disposed in close vicinity of a ceiling 3 of the kiln at appropriate intervals along the longitudinal axis of the kiln to constitute air blowing means.
  • a device such as a ring blower 9 which is a source of air is connected through a conduit 5 to the hollow pipes 2 to feed pressurized air into the hollow pipes, thereby blowing it downward through holes in the hollow pipes into the preheating zone of the kiln.
  • a valve 4 is provided in each of the hollow pipes 2 to adjust the flow rate of air therethrough depending on the quantity of the hot gas within the kiln.
  • the air blowing means may be divided into units each including one or more hollow pipes and mounted in the preheating zone in parallel with each other.
  • I and II show temperature curves in the upper and lower portions within the kiln, respectively, obtained by the prior art method while III and IV show temperature curves in the upper and lower portions within the kiln, respectively, obtained by the method according to the present invention.
  • the perforated hollow pipes may be protected by refractories to prevent the gas from dewing.
  • Slits are formed in the refractories for blowing the air therethrough.
  • Refractories may be positioned on the ceiling of the tunnel kiln to define an air chamber or chambers therebetween, from which air is blown through slits defined between the two adjacent refractories.
  • Materials, from which the hollow pipes are formed include such as pottery bodies, cordierite, mullite, silicon carbide, silicon nitride, alumina, or sialon, or heat-resisting steels or the like, those having heat and corrosion resistance properties and dense structure, any one of these materials can be selected depending on a required temperature region.
  • the pitch between the adjacent hollow pipes may be of about 100 to 1000 mm, preferably about 300 to 500 mm.
  • the diameter of each of the hollow pipes may be of about 10 to 100 mm, preferably 40 to 50 mm.
  • the holes in each of the hollow pipe, through which air is blown may be circular, oval or polygonal, but in general, circular holes are used.
  • the diameter of each of the holes in the hollow pipes is determined depending on the sectional area of the kiln and the flow rate and pressure of air or the like.
  • the holes in the hollow pipe may be tapered.
  • Refractories for protecting the perforated hollow pipes and the refractories for formation of the air chamber or chambers described hereinbefore which serves as the air blowing means may be of any suitable materials having heat and corrosion, resistant properties, and including calcium silicate, alumina, chamotte or the like.
  • the slits defined by the spaced-apart refractories can be in rectangular elongated form and have the width determined depending on the sectional area of the kiln and the flow rate and pressure of air.
  • the air is generally blown through the air blowing means in the vertical and downward direction, but may be blown at any angle.
  • the flow rate and pressure of air to be blown through the air blowing means depend on the quantity of the combustion gas generated in the kiln, but may be so adjusted that the air blow does not fling up debrises (such as brick debris, joint debris, porcelain debris and the like) in the lower portion of the kiln.
  • the kiln has its flat ceiling on which the air blowing means are located. However, if the ceiling of the kiln is arched, it is desirable to position the air blowing means along the arch of the ceiling.
  • a difference in temperature between the upper and lower portions of the preheating zone within the kiln is significantly reduced so that products can be uniformaly preheated, leading to an improved quality and yield of products.
  • a heat curve in the preheating zone is easily set so that the kiln can be operated with a high efficiency.
  • the combustion gas can be drawn to the inlet of the kiln, thus making it possible to utilize heat input effectively and conveniently and to provide an effect of energy saving.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Tunnel Furnaces (AREA)
  • Furnace Details (AREA)
EP85107266A 1984-06-14 1985-06-12 Verfahren zum Überwachen der Vorwärmzone eines Tunnelofens Expired - Lifetime EP0170828B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP59122217A JPS611991A (ja) 1984-06-14 1984-06-14 トンネル窯予熱帯域操窯方法
JP122217/84 1984-06-14

Publications (3)

Publication Number Publication Date
EP0170828A2 true EP0170828A2 (de) 1986-02-12
EP0170828A3 EP0170828A3 (en) 1988-07-20
EP0170828B1 EP0170828B1 (de) 1991-09-25

Family

ID=14830447

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85107266A Expired - Lifetime EP0170828B1 (de) 1984-06-14 1985-06-12 Verfahren zum Überwachen der Vorwärmzone eines Tunnelofens

Country Status (5)

Country Link
US (1) US4921422A (de)
EP (1) EP0170828B1 (de)
JP (1) JPS611991A (de)
KR (1) KR910000685B1 (de)
DE (1) DE3584199D1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023035191A1 (zh) * 2021-09-09 2023-03-16 付朝品 分布式高效节能环保工业窑炉

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6352378B1 (en) * 1998-11-12 2002-03-05 Canon Kabushiki Kaisha Accessory, apparatus to which the accessory is connected, accessory system, and lens adapter system composed of optical apparatus and a plurality of lens adapters
WO2024173994A1 (en) * 2023-02-24 2024-08-29 Iluka Resources Limited Processing apparatus

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD79811A (de) *
DE524247C (de) * 1931-05-04 Holding Ges Fuer Keramische We Verfahren zur Regelung des Abkuehlvorganges im Tunnelofen
US1725129A (en) * 1928-03-27 1929-08-20 Westinghouse Electric & Mfg Co Furnace
US2180041A (en) * 1934-07-02 1939-11-14 Durieux Jules Joseph Tunnel kiln
GB485578A (en) * 1936-11-19 1938-05-19 Gibbons Brothers Ltd Improvements in tunnel ovens
US3119166A (en) * 1961-08-01 1964-01-28 Ostermaier Leo Kiln for ceramics
US3170681A (en) * 1963-06-24 1965-02-23 North American Mfg Apparatus for scale free heating of metals
DE2254769C3 (de) * 1972-11-09 1985-06-05 Vereinigte Aluminium-Werke AG, 1000 Berlin und 5300 Bonn Durchlaufofen zum flußmittellosen Löten von Aluminiumwerkstoffen unter Schutzgas
US3860222A (en) * 1973-11-02 1975-01-14 Wall Colmonoy Corp Cooling system for vacuum furnaces
DE2357057B2 (de) * 1973-11-15 1976-12-30 Leisenberg, Manfred, 6312 Laubach Verfahren und vorrichtung zur luftmengenregelung in einem tunnelofen
DE2631352C3 (de) * 1976-07-13 1983-02-17 Bayer Ag, 5090 Leverkusen Verfahren zur partikelarmen Sterilisation
DE2657829A1 (de) * 1976-12-21 1978-06-22 Haessler Andreas Verfahren zur vergleichmaessigung der temperatur in tunneloefen
FR2405448B1 (fr) * 1977-10-07 1985-06-28 Welko Ind Spa Installation pour le controle de la conduite des fours a rouleaux pour la cuisson de matieres ceramiques ou similaires
JPS5746800U (de) * 1980-08-29 1982-03-15
IT1147425B (it) * 1981-10-14 1986-11-19 Carfer Srl Forno ceramico a rulli a combustione e raffreddamento modulati
US4493641A (en) * 1984-01-09 1985-01-15 Gladd Industries, Inc. Bake oven with manifold

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023035191A1 (zh) * 2021-09-09 2023-03-16 付朝品 分布式高效节能环保工业窑炉

Also Published As

Publication number Publication date
DE3584199D1 (de) 1991-10-31
JPS611991A (ja) 1986-01-07
KR910000685B1 (ko) 1991-01-31
EP0170828B1 (de) 1991-09-25
EP0170828A3 (en) 1988-07-20
KR860000527A (ko) 1986-01-29
US4921422A (en) 1990-05-01

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